My nephew once told me his grandmother had bought him a gun but told him he wasn’t allowed to use it to kill anything that wasn’t already dead. He was 5 at the time.

He’s now 17 and says he’s in high school, but I suspect he may have secretly gone to work for the Obama administration’s damage-control team.

Who else could have come up with the White House strategy to deal with the damaging revelations about the health-care system for America’s veterans — which was to make a big public show of firing someone who had already retired?

This is the perfect public-policy analogue to a gun that can be used only to kill the already-dead.

At first, last week’s dismissal of a high-ranking official with the Dickensian name of Dr. Robert Petzel seemed like the least the administration could’ve done to respond to the cover-up of the lax, lazy and downright inhuman treatment provided to veterans at the government-run hospitals across the country — hospitals specifically and solely dedicated to their care.

The supposed firing came a day after a disastrous congressional hearing featuring Petzel and Veterans Affairs Secretary Eric Shinseki.

But almost immediately, it turned out Petzel wasn’t dismissed at all; he’d announced his retirement months earlier and was only staying on until his successor was confirmed.

White House Chief of Staff Denis McDonough desperately sought to put a positive spin on this preposterous gambit when he told CBS’s Major Garrett, “There is no question that this is a termination of [Petzel’s] job there before he was planning to go.”

A few days later, White House Press Secretary Jay Carney said the American Legion, the largest private veterans group, considered Petzel’s firing a positive “step.”

That was nothing more or less than an outright lie. As Jonathan Karl of ABC pointed out, the Legion had actually called it “business as usual.”

Scandals at the hospitals tasked with the care of veterans and those still on military duty are nothing new.

The Vietnam vet-turned-protester Ron Kovic cast a horrifying light on the disgraceful care he was given at a Bronx VA hospital when he returned to the United States as a paralytic — initiating a hunger strike that led to the resignation of the VA’s head in 1974.

More recently, the Walter Reed Medical Center in Washington came under fire for disgraceful and unhealthful conditions at a facility just outside its gates where disabled soldiers returning from Afghanistan and Iraq were receiving special treatment.

Delays at VA hospitals were already enough of an issue that candidate Barack Obama used them in speeches in part to demonstrate that he wasn’t a standard-issue anti-war activist.

“No veteran should have to fill out a 23-page claim to get care, or wait months, even years, to get an appointment at the VA,” he said in August 2007.

Put all of this together and it was just too much for Ron Fournier of National Journal, a dean of the Washington press corps and someone who hardly counts as a conservative critic of the White House.

On Tuesday, he posted a piece called “Quiz: How Dumb Does Obama Think We Are?”

Obama’s general approach is to pooh-pooh troubles until that approach becomes untenable

Obama’s general approach is to pooh-pooh troubles until that approach becomes untenable, at which point the White House decides to broadcast its supposed anger — i.e., we’re told that Obama is “madder than hell” about the VA problems, an emotion literally no one seems to believe he’s experiencing.

Fournier worries that Obama thinks we’re stupid, but it seems just as likely the president’s team is taking so many blows its operatives are no longer able to respond coherently.

Bad news just keeps coming at the White House from every direction. One day it’s Benghazi. The next it’s the IRS scandal.

And every day come new poll numbers showing the Democratic Party on its way to a midterm defeat possibly more historic than the 2010 shellacking.

Maybe what we’re seeing here isn’t rank cynicism.

It’s that the administration is punch-drunk. My diagnosis: The White House is suffering from what you might call, if you were of a mind to do so, a political concussion.